Conclusions

A unique polarization effect of circular dichroism in elastic x-ray scattering, occurring when the scattered photon has a suitable fixed linear polarization, has been investigated for the case of scattering by randomly oriented ground-state atoms. Though it is a beyond-dipole-approximation effect, it has been shown to have significance, rising to $\approx$ 20% in cross sections for Z=92 at intermediate angles. The suitable polarization measurement involves measuring the difference in the scattering cross sections for right-handed and left-handed circularly polarized incident photons, for a final photon observed having a fixed linear polarization at 45^o with respect to the scattering plane. CD effects in scattering from randomly oriented targets vanish completely only if the final photon is chosen to have a linear polarization either parallel or perpendicular to the scattering plane.